The Benihisago (紅葫蘆; Literally meaning "Crimson Gourd") is a giant brown-coloured gourd with a red cloth around it. It is able to take a person's word soul (言霊, kotodama) hostage by saying the verbal command "record" (録音しろ, rokuonshiro). After the word soul has been drawn out by the Kōkinjō and then severed from their body by the Shichiseiken, it is absorbed into the gourd. Completing these conditions "curses" the victim; if they utter the word they have said the most during their life, they will be sucked into and trapped within the Benihisago. Saying a homophone of their most frequently spoken word, or even saying nothing at all for a certain amount of time, will also trigger the gourd's suction. If a victim starts to be sucked into Benihisago, the suction will stop if their most-used word changes. Kurama noted that whatever was sucked into the gourd was sealed away and could not come out, no matter what.[1] It can even keep those brought back with Summoning: Impure World Reincarnation sealed after the summoner releases the technique.

The Benihisago recording word souls.

The Benihisago is revered as one of the treasured tools of the Sage of the Six Paths. All five of the tools consume enormous amounts of chakra when used, so much so that normal humans would die after using the tools for only a short period of time. When the tools later came into the possession of Kumogakure, only the Gold and Silver Brothers due to their large chakra reserves were able to wield the treasures without fatal repercussions. When not in use, Ginkaku used the Kōkinjō to tie the gourd around his neck for easier transportation. When the rope is removed for combat, he must carry the gourd.

Trivia

The Benihisago is based on a tool from the Chinese classic "Journey to the West". In this story; there are two demon king brothers, known as the Great King Kinkaku (金角大王, Kinkaku-daiō) and the Great King Ginkaku (銀角大王, Ginkaku-daiō). The siblings possess five treasured tools, one of which is called the Crimson Gourd (紅葫蘆, Benihisago) and has the ability to suck in their opponents, melting them once they are trapped within.